Railway signaling



A 1938' G. R. PFLASTERER 2,126.659

RAILWAY SIGNALING Filed Dem 5, 1936 2 Sheets-Sheet 2 ia L INVENTOR HIS ATTORNEY V Patented Aug. 9, 1938 RAILWAY SIGNALING George R. Pflasterer, Swissvale, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application December 5, 1936, Serial No. 114,399

12 Claims.

My invention relates to railway signaling, and particularly to signaling involving wayside signals located along a trackway for governing the passage of trains.

A feature of my invention is the provisionof novel and improved apparatus for establishing a 5 States Patent No. 2,107,678 to Howard A Thomp- In the accompanying drawings, Figs. 1A and 1B are diagrammatic views which when placed end to end in the order named illustrate one form of apparatus embodying my invention.

Similar reference characters refer to similar parts in each view.

Referring to the drawings, the reference characters I and 2 designate the rails of a'stretch of railway track along which traific normally moves in the direction indicated by the arrows. These rails are divided by insulated joints 3 into a plurality of track sections W-X, X-Y, and Y-Z.

As here shown, each track section is divided by insulated joints 3 into at least two subsections IT, 2T, 3T, 4T, etc. Each subsection is provided with a track circuit which includes a track battery 4 connected across the rails at one end of the subsection and a track relay, designated by the reference character TR with a prefix the same as the numerical prefix in the reference character of the associated subsection, connected across the rails at the other end of the subsection.

To govern the passage of trains through the stretch of railway, a wayside signal designated by a suitable distinguishing reference character, is provided for each track section. Each of these signals includes an upper indication unit U and a lower indication unit L. These units may take any one of several forms of signal mechanism such as semaphore, color light, Searchlight, or position light. As here shown, each upper unit U is a semaphore arm capable of assuming a horizontal or stop position, a 45 or caution position, and a vertical or proceed position; and each lower unit L is a semaphore arm capable of assuming a horizontal or vertical position but not a 45 position.

For controlling the associated signal, each section is provided with a polarized signal control relay and a neutral signal control relay designated by the reference characters HD and J, respectively, each with a prefix the same as the reference character of the associated signal.

For controlling the associated relay J, each section is provided with a flasher relay and an auxiliary relay designated by the reference characters F and A, respectively, each with a prefix the same as the reference character of the associated signal. As will be explained more in detail hereinafter, the relays F and A cooperate to control the associated relay J in such a manner that such relay J can be energized only if relay F is energized. As here; shown, the relays F are of the flasher type having a definite operating voltage range, that is, the relays F will not operate unless the voltage supplied thereto is within predetermined maximum and minimum values. A relay of this type is described and claimed in an application for United States Letters Patent Serial No. 40,115, filed September 11, 1935, by Thomas J. OMeara and Benjamin Mishelevich, for Electrical relays.

For controlling the associated relays HD and F, each section is provided with a pair of con.- ductors each of which extends to the signal next in advance and each of which includes a front contact of each of the associated track relays.

Each section is provided with a source of energy (not shown) including a low voltage positive terminal, a high positive voltage terminal, and a common return terminal designated by the reference characters BL, BH, and C, respectively.

Each relay HD is connected to the associated pair of conductors by a resistor I I and each relay F is connected to the associated pair of conductors through a front neutral contact and a reverse polar contact of the associated relay I-ID. A shunt path is provided around each resistor I I which includes a back contact I2 of the associated relay J. As will be explained more in detail hereinafter, the pair of conductors for each section is at times supplied with energy of a relatively low value in the normal direction or in the reverse direction and at other times is supplied with energy of a relatively high value in the reverse direction. The pickup value of the relays HD is such that these relays will become picked up upon receiving energy of either value whereas the pickup value of the relays F which control the relays J is such that these relays will become picked up only upon receiving energy of the higher value. The relays F can, therefore, be picked up only when the associated relay HD is energized in the reverse direction and when the relays F are energized so that the associated relay 'J is energized, the resistors II are effective to limit the current flowing in the associated relay HD.

The relays HD and J control the magnitude and direction of the energy supplied to the line conductors for the section next in the rear.

The relays HD and J control the upper unit U and the lower unit L of the associated signal in the following manner: When relay HD is deenergized (see signal l9), both semaphore arms U and L are deenergized so that signal I0 is displaying both its semaphore arms in the horizontal position to indicate stop. When only the relay HD is energized in the reverse direction (see signal 9), a caution circuit for the semaphore arm U of that signal is closed over a path which passes from terminal BL over front contact I3 of relay SHD and semaphore arm U to terminal C. Semaphore arm U of signal 9, therefore, is in the caution position to indicate approach next signal prepared to stop. When relay HD is energized in the reverse direction and relay J also is energized (see signal 8), the caution circuit for semaphore arm U remains closed over front contact I4 of relay 8HD and a circuit is established for the semaphore arm of the lower unit L of that signal. This latter circuit passes from terminal B over front contact [4 of relay 8HD, reverse polar contact l5-I6 of relay 8HD, front contact ll of relay BJ, and semaphore arm L to terminal C. Signal 8, therefore, is displaying its upper semaphore arm U in the caution position and its lower semaphore arm L in the vertical position to indicate approach next signal at medium speed. When relay HD is energized in the normal direction (see signal 1), the caution circuit for the upper semaphore arm U will remain closed over front contact ill of relay 1HD and a proceed circuit for the semaphore arm U will be closed over a path which passes from terminal B over front contact l8 of relay 1HD, normal polar contact ill-29 of relay 1HD, and semaphore arm U to terminal C. Signal 1 is, therefore, displaying its upper semaphore arm in the vertical position to indicate proceed at normal speed. I shall conveniently term the four aspects of the signals, stop, approach, approach medium, and proceed, respectively.

As here shown, a train K is indicated diagrammatically in the section immediately to the right of location Z so that the signal I0 and. associated relays are all deenergized.

When signal I!) and associated apparatus is in this condition, relay 9HD is energized in the reverse direction by energy of a relatively low value over a circuit which passes from terminal BL at signal [0 through back point of contact 25 of relay IGHD, front contact 26 of relay 6TB, front contact 21 of relay 5TR, back contact 12 of relay 9J, relay Ell-ID, front contact 28 of relay 5TB, front contact 29 of relay 6TB, and back point of contact 30 of relay IOHD to terminal C.

When relay 9HD only is energized in the reverse direction, both relay 8HD and relay 8F are energized in the reverse direction by energy of relatively high value. The circuit for relay 8HD may be traced over a path which passes from terminal BH at signal 9 through back point of contact 3| of relay 9J, reverse polar contact 32-33 of relay SHD, front contact 34 of relay 9HD, front contact 35 of relay 4TB, front contact 36 of relay BTR, resistor H, relay I3HD, front contact 31 of relay 3TR, front contact 38 of relay 4TR, front point of contact 39 of relay SHD, reverse polar contact 40-4] of relay 9HD, and back point of contact 42 of relay 9J to terminal C. The circuit for relay 8F may be traced over the same path as just traced for relay 8HD except including front contact 43 and reverse polar contact 44-45 of relay 8HD instead of resistor l I and relay 8HD.

When relay 8F is energized, movable contact 46 is caused to alternate between engagement with fixed contacts 41 and 48 so that contacts 46-41 and 46-48 are alternately closed. The closing of contact 46-48 energizes relay 8A and the closing of contact 46-41 energizes relay 8.1 provided front contact 49 of relay 8A is closed. The slow releasing feature of relay 8A will insure that front contact 49 will remain closed during the open circuit periods and the slow releasing feature of relay 8J will insure that this relay also will remain picked up during open circuit periods.

When relay 8HD is energized in the reverse direction and relay 8J also is energized, relay 1HD is energized in the normal direction by energy of relatively low value over a path which passes from terminal BL at signal 8 through front point of contact 50 of relay 8J, normal polar contact 5l-52 of relay 8HD, front point of contact 53 of relay 8HD, front contact 54 of relay 2TH, front contact 55 of relay I'IR, relay 1HD, back contact l2 of relay 1J, front contact 56 of relay I'I'R, front contact 51 of relay ZTR, front point of contact 58 of relay 8HD, reverse polar contact 59-60 of relay 8HD, and front point of contact 6! of relay 8J to terminal C.

When relay 1HD is energized in the normal direction, the line conductors for the section next in rear of location W are supplied with energy of relatively low value in the normal direction over front points of contacts 62 and 63 of relay 1HD and normal polar contacts 64-65 and 66-61 of relay 1HD so that the signal (not shown) associated with such conductors will be displaying the normal proceed indication.

The resistors H, connected in series with the relays HD when the high voltage is supplied to the associated line circuit, are of such value that the normal current flowing in such relays is just sufficient to hold the relays picked up. The relays I-ID, therefore, will be certain to become released when the energization of the associated line conductors is changed from the high value to the low value. The shunt path including back contact l2 of the associated relay J is provided around the corresponding resistor II in order that the relay HD will receive sufficient energy for pickup.

As hereinbefore pointed out the relays J will respond only if energized with current of the high value and then only if the value of such current is within certain maximum and minimum limits. One purpose of a relay of this type is to prevent the signal controlled thereby from assuming a false proceed condition in the event the relay should become energized from a foreign current source of excessively high value. For example, if the line conductors for section Y-Z should become accidentally energized from a foreign current source of a value higher than the maximum limit of relay 9F, signal 9 would not change to the less restrictive approach medium indication but instead would continue to indicate the more restrictive approach indication. In other words, the safety factor of the system is enhanced because a foreign current in the signal line circuits must be within certain maximum and minimum limits in order to cause the relays F to respond thereto.

The retained. neutral: characteristic of. the relays HD is provided to avoid tumble-down of the signal circuits-to the rear during pole changing periods. For example, when the train K vacates the section immediately. to the right of location Z so that the direction of energization of relay BHD is changed from the reverse direction to the normal direction to cause signal 8 to. display the normal proceed indication, front contacts 53 and 58 of relay 8H1) do not become opened so that energization of the line circuit for section W--X is opened only during thetime polar contacts 51 and 59 of relay BI-ID are moving between their reverse position and normal position. This momentary interruption is of such short duration that the relay 'lHD will not become released so that tumble-down of the line circuits to the rear is avoided.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track, a pair of conductors for said section, means for supplying said pair of conductors with energy of a particular magnitude and direction or with energy of a higher magnitude in the same direction or with energy of said particular magnitude but in the other direction in accordance with traffic conditions in advance of said section, a polarized relay responsive to energy of either magnitude receiving current from said conductors. another relay responsive only if said energy of said higher magnitude is within certain predetermined maximum and, minimum values also receiving current from said pair of conductors, and tramc governing means for said section governed by said two relays.

In combination, a. section of railway track, a pair of conductors for said section, means for supplying said pair of conductors with energy of a particular magnitude and directionor with energy of a higher magnitude in the same direction or with energy of said particular magnitude but in the other direction in accordance with traffic conditions in advance of said section, a polarized relay responsive to energy of either magnitude receiving current from said conductors, another relay responsive only if said energy of said higher magnitude is within certain predetermined maximum and minimum valuesalso receiving current from said pair of conductors, a signal for said section, and means governed by said two relays for causing said signal to display one indication when only said polarized relay is energized in said particular direction or another indication when both said relays are energized or still another indication when only said polarizedrelay is energized in said other direction.

3. In combination, a sectionof railway track,

- a pair of conductors for said section, means for rection is. within predetermined maximum and, minimum values, a signal for said. section, and means governed. by said two relays for causing said signal to indicate approach when said polarized relay only is energized in, the reverse direction or to indicate "approach medium when said'polarized relay is energized, in the reverse direction and said neutral relay is alsoenergized or to, indicate proceed when said polarizedv relay is energized in the normal direction.

4. In combination, a section of railway track, a pair of. conductors for said section, means for supplying said pair of conductcrswith energy of a relatively low value in the reverse direction orwith energy of a relatively high value in the reverse direction or with energy of said relatively low value in the normal direction in accordance with traffic conditions in advance of said section, a polarized relay responsive to energy of either value receiving current from said pair of conductors, a neutral relay, means also receiving current from said pair of conductors effective to pick up said neutral relay effective only if the energy. of said high. value is in the reverse direction and is within certain predetermined maximum and: minimum values, a, signal for said-section comprising a, first indication unit and a second indication unit, said first indication unit being a semaphore arm capable of assuming a stop and a caution as well as a proceed position and said second indication unit being a semaphore arm capable of assuming, a proceed and a stop position, .a caution circuit for the semaphorearm of the first unit including a front neutral contact of said polarized relay, a proceed circuit for the semaphore arm of the first unit including a front neutral contact of said polarized relay and a normal polar-contact of said polarized relay, and a circuit for the semaphore arm of said second unit including a front neutral and a normal polar contact both of said polarized relay as well as a front contact of said neutral relay.

5. In combination; a forward and a rear section, of railway track, a polarized relay and a neutral relay for said forward section, means effective when the forward section is. unoccupied to energize only saidpolarized relay in the reverse direction or only said polarized relay in the normal direction or both said, relays according to traffic conditions in advance of said forward section, a pair of conductors for the rear section controlled by trafiic conditions in that section, means effective to supply said conductors with energy of relatively low value in the reverse direction when said polarized relay is deenergized, means effective to supply said conductors with. energy of said relatively high value in the reverse direction when said polarized relay only is energized in the reverse direction, and means efiective to supply said conductors with energy of said relatively low value in the normal direction when said neutral relay is energized provided said polarized relay also isenergized in the reverse direction.

6'. A, railway signal system comprisinga stretch oftrack divided, into sections, a track circuit ineluding a track relay for each section, a pair of line conductors for each section each including a front contact of said track relay, means for each section for supplying the pair of conductors for the section next in rearwith energy of a relatively low value in, one direction or with energy of .a relatively high value in said one direction; or with energy of said relatively low value in the other direction in accordance with trafiic conditions in advance, a polarized relay for each section responsive to energy of either value receiving current from the associated conductors, a neutral relay for each section, means responsive only to energy of said high value and then only if said energy of high value is within predetermined maximum and minimum values also receiving current from the associated conductors for controlling said neutral relay, and traffic governing means for each section controlled by the associated neutral and polarized relays.

7. A railway signal system comprising a stretch of track divided into sections, a track circuit including a track relay for each section, a pair of line conductors for each section each including a front contact of said track relay, means for each section for supplying the pair of conductors for the section next in rear with energy of a relatively low value in one direction or with energy of a relatively high value in said one direction or with energy of said relatively low value in the other direction in accordance with traffic conditions in advance, a polarized relay for each section responsive to energy of either value receiving current from the associated conductors, a neutral relay for each section, means for each section responsive only to energy of said high value and then only if said energy of high value is within predetermined maximum and minimum values also receiving current from the associated conductors for governing the associated neutral relay, a signal for each section, means effective when only the polarized relay of a section is energized in said one direction to cause the associated signal to display a particular indication, means effective when the polarized relay of a section is energized in said one direction and said neutral relay also is energized to cause the associated signal to display a different indication, and means effective when only said polarized relay is energized in said other direction to cause the associated signal to display still a different indication.

8. In combination, a stretch of railway track divided into sections each provided with a track circuit including a track relay, a pair of conductors for each section each including a front contact of the associated track relay, means effective when one section is occupied to supply the conductors for the section next in rear of such occupied section with energy of a particular magnitude and direction, means then effective to supply the conductors for the section second in rear of such occupied section with energy of a different magnitude but in the same direction, means then effective to supply the conductors for the section third in rear of such occupied section with energy of said particular magnitude but in the other direction, and traffic governing means for each section selectively responsive to the direction and magnitude of the energy supplied to the associated conductors.

9. In combination, a forward and a rear section of railway track, a polarized relay and a neutral relay for said forward section, means effective when the forward section is unoccupied to energize only said polarized relay in the reverse direction or to energize said polarized relay in the reverse direction as well as said neutral relay or to energize only said polarized relay in the normal direction according to traffic conditions in advance of said forward section, a pair of conductors for the rear section controlled by traffic conditions in that section, a high voltage terminal and a low voltage terminal, means effective to connect said conductors in one direction with said low voltage terminal when said polarized relay is deenergized, means effective to connect said conductors in the same direction with said high voltage terminal when said polarized relay only is energized in the reverse direction, and means effective to connect said conductors with said low voltage terminal in the other direction when said polarized relay only is energized in the normal direction or when said neutral relay is energized provided said polarized relay is also energized in the reverse direction.

10. In combination, a stretch of railway track divided into sections each provided with a track circuit including a track relay, 9. pair of conductors for each section each including a front contact of the associated track relay, means effective when one section is occupied to supply the conductors for the section next in rear of such occupied section with energy of a relatively low value in one direction, means then effective to supply the conductors for the section second in rear of such occupied section with energy of a relatively high value in said one direction, means then effective to supply the conductors for the section third in rear of such occupied section with energy of said relatively low value in the other direction, and signaling means for each section selectively responsive to the value and direction of energy supplied to the associated line conductors.

11. In combination, a section of railway track, a pair of conductors for said section, means for supplying said pair of conductors with current of a particular magnitude or with current of a different magnitude in accordance with traffic conditions in advance of said section, a first means responsive to energy of either magnitude receiving current from said pair of conductors, a second means responsive only to energy of said different magnitude and then only if the current of such different magnitude is within predetermined maximum and minimum values also receiving current from said pair of conductors, and traffic governing means for the section controlled by said first and second means.

12. In combination, a section of railway track, a pair of conductors for said section, means for supplying said pair of conductors with energy of a particular magnitude and direction or with energy of a different magnitude in the same direction, or with energy of said particular magnitude but in the other direction in accordance with traffic conditions in advance of said section, a polarized. relay responsive to energy of either magnitude receiving energy from said conductors, a supply circuit, means controlled by a polar contact of said polarized relay for supplying current from said pair of conductors to said supply circuit, a relay responsive to the supply of current to said supply circuit and being operative only if the energy supplied thereto is within certain maximum and minimum values, whereby said relay is operated only when current of a particular polarity is supplied to said pair of conductors and then only if the magnitude of the current is within certain values, and traffic governing means for said section governed by said two relays.

GEORGE R. PFLASTERER. 

